Re: RO unit, fresh carbon block and chlorine

[Dave Gomberg <gomberg@wcf.com>]

>Date: Fri, 11 Jun 1999 08:41:29 -0700
>From: Wright Huntley <huntley1@home.com>
>
> I haven't the foggiest what a "carbon block" is. The simple solution
>is to just use some Amquel and forget it.
>
>That said:
>
>If the activated-charcoal filter cartridge is defective, the TFC membrane
>will be damaged quickly, and the tds of the "RO" water will start to rise.
>Using an RO unit without testing for tds (or at least dGH) is folly.
>Filtering through carbon must be done *very* slowly, and with the proper
>kind of charcoal, if all chloramine is to be removed. Time of contact is the
>most important issue. Type of activated charcoal is important, too. Some,
>like the granules sold at aquarium shops are essentially worthless. OK for
>clearing dye, but ineffective on chlorine.
>
>Because the water tested positive for chlorine is not evidence that
>chloramine is not in use. They react identically on a chlorine test. Amquel,
>and not some hypo-based dechlor product is called for. I seriously doubt if
>a community the size of Nashville is not on chloramine at this point. SF is
>the *only* city in the US of over 500K people that does not have it, and
>that is because they don't even *need* chlorine in most of the SF system.
>
>Small molecules like ammonia and chlorine pass through an RO membrane just
>as easily as water. *No* RO unit removes them. The activated charcoal filter
>should do it at normal flow rates for RO conversion. If not, a valve to
>reduce flow might improve extraction.
>> >From: Kelly Beard <apistogramma@home.com>
>> >Last week I did a water change and lost a neon and noticed respiratory
>> >stress on the hatchet fish.  The cichlids seemed fine.  I make water
>> >change water with RO unit, trash can, and appropriate KH and GH
>> >reconstituters.  Irritated with the death of the last neon, I took a
>> >sample of my water to the LFS.  I described to him the situation, and he
>> >was puzzled.  On a whim, I asked if he could do a test for chlorine.  He
>> >said "surely not", but I insisted that something was up with this
>> >water.  Bingo, I was right.  Ample amounts of chlorine.  I found a
>> >chlorine test kit today.  Apparently Nashville, TN tap is just chlorine,
>> >not chloramine.  But, what I want to know is, why should an RO unit leak
>> >chlorine?  My carbon unit was brand new - but there's a twist.  The
>> >carbon block was purchased from   Home Depot or Lowe's and is meant for
>> >a home water unit.  I bought the best one, something around $33, a CB-3,
>> >made by Omni, I believe.  The label said 99.9% of chlorine removed.
>> >>From what I can tell, none is being removed.  I carbon block fits tight
>> >- water can't be getting around the unit.
>> >
>> >So, I ordered 4 carbon blocks meant for my Coralife RO unit from That
>> >Fish Place, thinking that maybe the carbon block is not meant for an RO
>> >unit.  Maybe the flow of water is too high, or something.


--
Dave Gomberg, San Francisco            mailto:gomberg@wcf.com
The latest in CO2 news:     http://www.wcf.com/co2iron 
Tropica MasterGrow in the USA:      http://www.wcf.com/tropica 
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